JPH07183049A - Method for estimating deteriorated state of storage battery and device therefor - Google Patents

Abstract

PURPOSE:To determine an appropriate battery replacement time by estimating the deteriorated state of a storage battery without stopping operation of equipment that uses the storage battery. CONSTITUTION:The charging voltage of a storage battery is measured using an A/D converter 8 on the day before the expected date of measurement, to determine whether or not the storage battery 3 has been floating charged or trickle charged. If the storage battery 3 has been floating charged or trickle charged, the charging current of the storage battery is measured over a predetermined sampling period using a shunt resistance 4, an amplifier 5 and the A/D converter on the expected date of measurement. The fluctuation width of measurements of the charging current sampled is compared with a reference fluctuation width by a microprocessor 7, and when the fluctuation width of the measurements is greater than the reference fluctuation width, the storage battery is determined to be dead, which is indicated in a display 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage battery deterioration state estimating method and apparatus for determining the replacement time of a storage battery that is floatingly charged or trickle charged.

[0002]

2. Description of the Related Art As a conventional deterioration state estimation method for determining the replacement time of a storage battery (generally a lead storage battery) that is floating-charged or trickle-charged, a method of measuring the specific gravity of an electrolytic solution is most commonly used. I've been told. However, in a completely sealed lead-acid battery or the like, the specific gravity of the electrolytic solution cannot be directly measured. Therefore, for example, an electrode for measuring the specific gravity of the electrolytic solution (a lead dioxide electrode in a lead-acid battery) is disclosed as disclosed in Japanese Patent Publication No. 61-294711. There have been proposed methods such as a method of measuring the specific gravity of an electrolytic solution installed in a battery case, a method of measuring an open voltage, and a method of measuring impedance.

[0003]

Among the above-mentioned conventional deterioration state estimation methods, in the method of installing the lead dioxide electrode for measuring the specific gravity of the electrolyte in the battery case, the potential of the lead dioxide becomes unstable, so that it is periodically There is a problem that maintenance such as charging is required and the structure becomes complicated. Further, the method of measuring the open voltage has a problem that the measurement cannot be performed unless the operation of the device using the storage battery is stopped and the floating charge or the trickle charge is stopped. The same applies to the method of measuring impedance because it is affected by noise such as ripple current. The most reliable method is to measure the discharge capacity of the battery, but this method requires a long time and trouble after stopping the operation of the equipment, and thus it is difficult to perform it regularly.

It is an object of the present invention to provide a method and apparatus for estimating the deterioration state of a storage battery without stopping the operation of the storage battery using equipment.

Another object of the present invention is to provide a method and apparatus for periodically estimating the deterioration state of the storage battery without stopping the operation of the storage battery using device.

[0006]

In order to solve the above problems, in the deterioration state estimating method for a storage battery according to the present invention, first, the charging current of the storage battery that is floating-charged or trickle-charged is measured at a predetermined sampling cycle. To do. Then, the fluctuation range of the measured value of the sampled charging current is compared with the reference fluctuation range, and when the fluctuation range of the measured value is larger than the reference fluctuation range, the life of the storage battery is determined. The storage battery to be measured may be a sealed lead storage battery.

The apparatus of the present invention for carrying out the above method of estimating the deterioration state of a storage battery is a floating charge state judging means A for judging whether the storage battery is floating charged or trickle charged.
And charging current measuring means B for measuring the charging current at a predetermined sampling period when the storage battery is floating-charged or trickle-charged, and the fluctuation range of the measured value of the sampled charging current and the reference fluctuation range are compared. Then, the fluctuation range determination means C for determining the life of the storage battery when the fluctuation range of the measured value is larger than the reference fluctuation range, and the display means D for displaying the determination result of the fluctuation range determination means. .

[0008]

In the case of a lead storage battery, the main cause of deterioration of the storage battery that is floating-charged or trickle-charged is the corrosion of the anode grid and the accompanying elongation. Due to the corrosion and elongation of the anode grid, the current collecting ability of the grid is reduced, the peeling phenomenon between the active material and the grid occurs, and the amount of active material that reacts effectively decreases. Leading to. Further, at the end of life, the corroded grid body may be broken, or the anode grid body extending in the stacking direction may come into contact with the cathode plate to cause a short circuit. Phenomena such as separation of the active material from the grid, disconnection of the grid, and short-circuiting between electrode plates are all physically unstable contact states, and this unstable contact state is the time of floating charging or trickle charging current. Appears electrically as a dynamic fluctuation. Therefore, the charging current of a storage battery that is floating-charged or trickle-charged is measured at regular intervals, and if the fluctuation range of the measured value is large,
It is assumed that the above-mentioned phenomena such as separation between the active material and the lattice, disconnection of the lattice, and short-circuiting between the plates have occurred, that is, the measured storage battery has deteriorated and it is time to replace the battery. Will be possible.

FIG. 4 shows an example of a change in the trickle charge current of a battery at the end of its life, and FIG. 5 shows an example of a change in the trickle charge current of a battery at the end of its life. As is clear from a comparison between FIG. 4 and FIG. 5, the trickle charging current at the end of the life obviously has a wider range of temporal variation than that at the end of the life. In addition, FIG. 6 shows an example of the temporal fluctuation range of the trickle charge current and the change of the discharge capacity in the life test. In this example, the fluctuation range of the trickle charging current is shown by the difference between the maximum value and the minimum value of the values measured at 1024 points per second. As shown in FIG. 6, the fluctuation range of the trickle charging current increased from slightly before the end of life, indicating that the deterioration of the battery had progressed.

Therefore, when the deterioration state estimation method of the present invention is used, the deterioration state of the storage battery that is floating or trickle charged is favorably estimated, and the battery replacement timing is appropriately determined. Further, the method of the present invention is particularly useful for estimating the deterioration state of a sealed lead acid battery. Then, in the apparatus of the present invention, the deterioration state estimation method of the present invention is well implemented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The present embodiment is an example in which the present invention is applied to a system for floating charging a stationary sealed lead acid battery rated at 200 Ah. FIG. 1 is an explanatory view showing the outline of the apparatus of this embodiment.
A sealed lead acid battery 1 that is floatingly charged includes a charger 2 and a load 3.
, The storage battery 1 is always floating-charged by the charger 2. A shunt resistor 4 for detecting a floating charging current is inserted in series between the storage battery 1 and the charger 2. The voltage across the shunt resistor 4 is amplified by the DC amplifier 5 to obtain A /
It is input to the D converter 6. The output of the A / D converter 6 is connected to the microprocessor 7, the floating charge current is measured by the A / D converter 6 when measuring the fluctuation of the floating charge current, and the fluctuation range of the measured value is evaluated by the microprocessor 7. . In addition, another A /
The output of the D converter 8 is connected. The A / D converter 8 is for measuring the voltage of the storage battery 1 and is for checking the state of charge of the storage battery 1. Further, the microprocessor 7 is connected to an indicator 9 including an LED for displaying the battery replacement time. In this embodiment, the shunt resistor 4, the DC amplifier 5, and the A / D converter 6 constitute the charging current measuring means B, and the A / D converter 8 and the microprocessor 7 constitute the floating charging state determining means A. The display 9 constitutes display means, and the microprocessor 7 constitutes fluctuation range determination means.

In this embodiment, the microprocessor 7 is
The / D converter 8 is operated to measure the charging voltage of the storage battery 1, and if the charging voltage from about one day before the measurement date of the charging current to the measurement date is within the preset setting range for floating charging, the storage battery 1 is determined to be in the floating charge state, that is, in the measurable state. The measurement of the charging voltage for determining whether or not the measurement is possible does not have to be performed on the day before the scheduled measurement date. For example, the measurement may be performed many days before the scheduled measurement date, or the measurement may be performed on the scheduled measurement date. The measurement time is not limited to 24 hours and may be any time as long as it is necessary and sufficient for determining the state of charge. The microprocessor 7 determines whether or not the storage battery is in a measurable state.

After determining that the storage battery is in the measurable state, the microprocessor 7 measures the floating charging current at a predetermined time interval, that is, the sampling period, based on the output of the A / D converter 6 on the scheduled measurement day. The fluctuation range of the charging current is detected and evaluated by comparing the fluctuation range with a reference value.

Further, the microprocessor 7 measures the fluctuation range of the charging current as described above at regular intervals. FIG. 1 is a flow chart showing an example of a software algorithm used when the present embodiment is implemented using the microprocessor 7. In this embodiment, the scheduled measurement date is set every month, and the storage battery 1 is set on the day before the scheduled measurement date.
Is in floating charge. After that, the floating charge current is sampled at 1024 points at intervals of 1 second, and the width of the fluctuation of the floating charge current is measured. As a method of evaluating the fluctuation range of the floating charging current, there is a method of evaluating the range of the maximum value and the minimum value as shown in FIG. 4, but in this embodiment, the effect of sporadic noise is removed, so The standard deviation of the measured values at 1024 points was evaluated. In this embodiment, 1
The charging current is measured every month, and when the standard deviation of the measured values exceeds 10 mA, the storage battery 1 deteriorates and the display 9 indicates that it is time to convert.

In the above embodiment, the standard deviation value of the measured value was used as an evaluation method of the measured value fluctuation range of the obtained floating charging current. However, depending on the load, ripple current or periodic noise may change the charging current. In some cases, the fluctuation range of the charging current is apparently measured to be large. In such a case, reduce the noise or ripple current component with a filter, or perform Fourier transform on the obtained charging current data to remove the ripple current or periodic noise component and set a predetermined standard. Compare with the value.

Although the present embodiment is an embodiment for estimating the life of a lead storage battery that is floating-charged, the present invention can be applied to the life determination of a trickle-charged storage battery.

Next, preferred embodiments of the present invention will be described below.

(Embodiment 1) It is determined whether a sealed lead-acid battery is floating-charged or trickle-charged, and when the battery is floating-charged or trickle-charged, a charging current is measured at a predetermined sampling cycle. Then, comparing the fluctuation range of the measured value of the sampled charging current with a reference fluctuation range, and when the fluctuation range of the measured value is larger than the reference fluctuation range, it is determined that it is time to replace the storage battery. A method for estimating the deterioration state of a sealed lead-acid battery.

The purpose of this embodiment is to provide a sealed sealed lead-acid battery that is floating-charged or trickle-charged and can be used for life determination or battery replacement timing determination without stopping the operation of equipment connected to the storage battery. A method of estimating the deterioration state of a lead-acid battery. In this embodiment, since the deterioration state is determined after determining whether the sealed lead acid battery is in the state of floating charge or trickle charge in advance, the accuracy of the determination result is high.

(Embodiment 2) A method for estimating a deterioration state of a storage battery according to embodiment 1, wherein the fluctuation range of the measured value is obtained by a standard deviation.

The purpose of this embodiment is to improve the determination accuracy of the deterioration state estimation method. When the fluctuation range is calculated by the standard deviation, the fluctuation range measurement accuracy increases.

(Embodiment 3) A sealed lead-acid battery is floating-charged based on whether or not the charging voltage is within a preset range by measuring the fluctuation of the charging voltage from the day before the scheduled measurement date to the scheduled measurement date. Alternatively, if it is determined whether the battery is trickle charged, and if the storage battery is floating charged or trickle charged, the charging current is measured at a predetermined sampling period on the scheduled measurement day, and the sampling charging current is measured. Estimating the deterioration state of the sealed lead-acid battery, characterized in that the standard deviation of the values is compared with the life judgment reference value, and when the standard deviation is larger than the life judgment reference value, it is judged as the life of the storage battery. Method.

An object of this embodiment is to provide a method for estimating the deterioration state of a sealed lead acid battery, which enables highly accurate life judgment or battery replacement timing judgment of a sealed lead acid battery that is floatingly charged or trickle charged. Especially. In this embodiment, since it is determined whether the sealed lead acid battery is in the floating charge or trickle charged state in advance from the fluctuation state of the charging voltage from the day before the scheduled measurement date to the scheduled measurement date, the sealed lead acid battery is determined. It is possible to accurately determine whether the storage battery is floating-charged or trickle-charged.

(Embodiment 4) A method for estimating the deterioration state of a sealed lead-acid battery according to embodiment 3, wherein a noise or ripple current component is removed from the measured value when the charging current is measured. The purpose of this embodiment is to allow measurements to be made independent of noise or ripple current.
When the fluctuation range of the charging current is measured after removing the noise or the component of the ripple current from the measured value as in the present embodiment, the measurement accuracy is significantly increased.

(Embodiment 5) The method for estimating the deterioration state of a sealed lead-acid battery according to embodiment 4, wherein the noise or ripple current component is removed by Fourier transform.

The purpose of this embodiment is to remove noise or ripple current by arithmetic processing. When noise or ripple current is removed by Fourier transform as in this embodiment, a desired noise or ripple current can be easily removed using a computer.

(Embodiment 6) A sealed lead-acid battery is floating-charged based on whether or not the charging voltage is within a preset range by measuring the fluctuation of the charging voltage from the day before the scheduled measurement date to the scheduled measurement date. Alternatively, a floating charge state determining means for determining whether or not the battery is trickle charged, and a charging current measuring means for measuring the charging current at a predetermined sampling period on the scheduled measurement date when the storage battery is floating or trickle charged. A fluctuation range determination means for comparing the standard deviation of the measured values of the sampled charging current with a life determination reference value, and determining the life of the storage battery when the standard deviation is larger than the life determination reference value. And a display unit that displays the determination result of the fluctuation range determination unit.

(Embodiment 7) The deterioration state estimating apparatus for a sealed lead-acid battery according to embodiment 6, wherein the charging current measuring means is provided with a filter for removing a noise or ripple current component.

(Embodiment 8) The deterioration state estimating apparatus for a sealed lead storage battery according to embodiment 6, wherein the charging current measuring means includes means for removing the noise or ripple current component by Fourier transform.

[0030]

As described above, according to the deterioration state estimating method for a storage battery according to the present invention, the charging current of the storage battery that is floating-charged or trickle-charged is measured at a predetermined sampling cycle, and the sampled charging is performed. The fluctuation range of the measured current value is compared with the reference fluctuation range, and when the fluctuation range of the measured value is larger than the reference fluctuation range, it is determined that the life of the storage battery has been reached. It is possible to easily estimate the deterioration state of the battery and appropriately determine the battery replacement timing.

Further, according to the deterioration state estimating apparatus for a storage battery of the present invention, the deterioration state estimating method of the present invention can be implemented extremely well.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a configuration of a storage battery deterioration state estimation device of the present invention.

FIG. 2 is an explanatory diagram showing an embodiment of the present invention.

FIG. 3 is a flow chart showing one of the algorithms of the software used to operate the microprocessor.

FIG. 4 is a characteristic curve diagram showing an example of temporal changes in trickle charging current in a storage battery at the end of life.

FIG. 5 is a characteristic curve diagram showing an example of temporal change of trickle charging current in a storage battery in the middle of life.

FIG. 6 is a characteristic curve diagram showing an example of variation in trickle charge current and variation in battery discharge capacity over a life test period.

[Explanation of symbols]

 A floating charge state determination means B charging current measurement means C fluctuation range determination means D display means 1 lead acid battery 2 charger 3 load 5 DC amplifier 6,8 A / D converter 7 microprocessor 9 display

Claims (3)

[Claims] 1. The measurement is performed by measuring a charging current of a storage battery that is floating-charged or trickle-charged at a predetermined sampling period, and comparing a variation range of a measured value of the sampled charging current with a reference variation range to perform the measurement. A method of estimating the deterioration state of a storage battery, wherein the deterioration state of the storage battery is determined when the fluctuation range of the value is larger than the reference fluctuation range. 2. The deterioration state estimating method for a storage battery according to claim 1, wherein the storage battery is a sealed lead storage battery. 3. A floating charge state determining means for determining whether the storage battery is floating-charged or trickle-charged, and a charging current is measured at a predetermined sampling period when the storage battery is floating-charged or trickle-charged. The charging current measuring means is compared with the variation width of the sampled charging current measurement value and the reference variation width, and when the variation width of the measurement value is larger than the reference variation width, it is determined that the storage battery has reached the end of its life. A deterioration state estimating device for a storage battery, comprising: a fluctuation range determining means; and a display means for displaying a judgment result of the fluctuation range judging means.